Hook positioner



5 Sheets-Sheet 1 Filed Dec. 5 1950 s a m2 7 M H m Jan. 24, 1956 w. P.GAINES 2,732,244

HOOK POSITIONER Filed Dec. 5, 1950 r 5 Sheets-Sheet 2 Jan. 24, 1956 w.P. GAINES 2,732,244

HOOK POSITIONER Filed Dec. 5, 1950 5 Sheets-Sheet 3 A I! 58 (g m: GINVENTOR- Jan. 24, 1956 w. P. GAINES 2,732,244

HOOK POSITIONER Filed Dec 5, 1950 5 Sheets-Sheet 4 VENTOR. 60/4464GflM/fs Jan. 24, 1956 w. P. GAINES 2,732,244

HOOK POSITIONER Filed Dec. 5, 1950 5 Sheets-Sheet 5 F26. 11. INVENTOR.

wad/7M p. G'fl/AES W {Max United States Patent- O HOGK POSITIONERWilliam P. Gaines, Vista, Calif.

Application December 5, 1950, Serial No. 199,229

Claims. (Cl. 294-82) This invention relates generally to hook structuresand the like of the type generally used to support and to raise or lowerwell casing, drill pipe, Well tubing or sucker rods in a well. Theinvention is more particularly directed to an improvement in suchstructures to facilitate the handling of well pipe or rods when loweringor raising them into or out of a well.

When a well is being drilled for the production of fluids such as oil,gas or water, it is customary to support the string of drill pipe by adrilling hook structure suspended from a traveling block which in turnis suspended in the derrick by a drilling line. When the drilling bitbecomes dull the drill string, which comprises threadedly connectedsections, is pulled from the well and the disconnected sections orstands are stacked upright in the derrick. After replacement of the bitthe drill string is run back into the well by screwing the standstogether and lowering the drill string the length of a stand as eachstand is added. During these operations the drill string is supported byan elevator flexibly suspended from the drilling hook structure by apair of elevator links. The elevator is composed of pivotallyinterconnected sections which may be swung apart to provide a lateralopening permitting lateral insertion of the pipe into the bore of theelevator and then closed and latched about the pipe.

The manipulation of the upper ends of the disconnected stands of pipe isperformed or controlled by an operator on a platform mounted in theupper portion of the derrick, this operator being usually referred to asthe derrick man. When pulling the pipe from the well, or coming out ofthe hole, in accordance with conventional practice it is the derrickmans duty'to unlatch the eleva tor from each stand and to move the upperend of the stand into position in the pipe rack. When running the pipeinto the well, or going in the hole, it is his duty to move the upperend of each stand into position to be inserted laterally into theelevator bore, and to close and latch the elevator unless the elevatoris of a type which is automatically closed and latched upon insertion ofthe pipe thereinto. It will be apparent that in order to avoid delay andinterruption of the cycle of operation, when going in the hole the emptyelevator should be properly oriented as it is raised in the derrick, sothat its lateral opening faces the sand of pipe to be engaged.Heretofore it has not been possible to insure such proper orientation ofthe elevator at this time, for the following reasons.

For various practical reasons drilling hook structures embody thefollowing essential elements and features:

(1) A hook member or its equivalent load-carrying member by which thepipe is supported;

(2) A supporting member adapted to be attached to and supported by thetraveling block;

(3) An axially slidable and rotative connection between the hook memberand the supporting member whereby the hook member may rotate about avertical axis and may have limited axial movement relative to thesupporting member;

"ice

(4) Spring means between the members resisting downward movement of thehook member relative to the supporting member; and

(5) Means for releasably locking the. hook member against rotationwithout interfering with the aforesaid relative axial movement.

The purpose of the relative axial movement and of the spring loading ofthe hook member is to cause the hook to raise the stand of pipe a fewinches as it is unscrewed from the drill string and thus avoid damage tothe joint threads, the spring having suflicient force to expand underthe load of a single stand of pipe. The purpose of the rotativeconnection and of the rotation lock is to enable the hook member to berotated into different positions and to be locked against rotation inany one of several positions. For instance, during the drillingoperation a portion of the torque applied to the drill string by therotary table is imparted to the rotary swivel, which must be restrainedagainst rotation because of the mud hose connected thereto. By lockingthe hook member against rotation, the rotary swivel is prevented fromrotating.

When coming out of the hole it is customary to lock the hook againstrotation, in such position that the elevator opening is disposed towardthe pipe rack. However, when going in the hole there is frequently atendency for the drill string to be rotated by the drill bit as itdescends, due to a corkscrew efiect which is most pronounced in crookedwells. If the upper end of the drill string were held against rotationunder these circumstances, there is a danger that one of the threadedjoints in the drill string may become loosened and allow a portion ofthe drill string to drop to the bottom of the well. For this reason itis considered essential that the hook swivel lock be released whilegoing in the hole. Consequently each time the elevator is unlatched andremoved from the pipe at the floor level and before it is raised to theupper portion of the derrick to engage another stand of pipe, the hook,links and elevator must be manually rotated by a crew member to aposition wherein the elevator opening faces the next stand of pipe. Thisnecessitates a pause in the operating cycle, slowing down the operation.Even after being properly oriented at the floor level the elevatorfrequently turns slightly during its ascent, due to vibration andswaying, so that when it reaches the upper portion of the derrick itslateral opening is not directed toward the stand of pipe to be insertedtherein. This results in additional delay which cannot be avoided bylocking the hook at the floor level in the proper position, for thereason that when it is in the upper position the lock is not accessibleto the derrick man for release by him to permit free rotation duringsubsequent lowering of the drill string.

The instant invention, when applied to spring-type drilling hookstructures, overcomes this difficulty and reconciles the twoaforementioned conflicting conditions by providing means whereby thehook is automatically rotated into a predetermined position upon releaseof the weight of the drill string, and is maintained in such positionuntil the weight of the drill string is again imposed on it, whereuponthe hook member is rendered freely r0- tatable with respect to itssupporting member. According to one aspect of the instant invention, thestored energy in the hook spring is used to rotate the hook into thedesired position. More specifically, this application of the inventioncontemplates the provision of coacting cam and follower elements, oneassociated with the hook memher and the other associated with thesupporting member and cooperating to rotate the hook member into apredetermined position during expansion of the spring upon release ofthe applied load.

In different drilling rigs the location of the pipe rack with respect tothe drawworks varies considerably, and

hence the elevator should be capable of being positioned with itslateral opening facing in any desired direction. Furthermore, difierentmakes and types of elevators have lateral openings which face indirections which vary somewhat with respect to the hook member.Accordingly, another aspect of the instant invention contemplatesadjustability of one of the cam members throughout an entire revolutionabout the axis of rotation of the hook member, into any one of aplurality of angularly spaced positions, and preferably permittingadjustment by small increments so that a predetermined position whichthe unloaded elevator automatically assumes may be selected to provideoptimum working conditions for the derrick man.

In addition to its advantages in improving operating conditions whenincorporated in a drilling hook structure, the instant invention is alsoapplicable to tubing hook structures and sucker rod hook structures.When running strings of well production tubing or sucker rods into orout of the well, the disconnected stands are racked upright in thederrick or the mast of the pulling unit, and operating conditions aregenerally similar to those prevailing in the running of a string ofdrill pipe. An appreciable saving in time and effort may be efiected byincorporating in a tubing hook structure or sucker rod hook structurecooperating elements operable to automatically orient the hook memberand hence the elevator into a predetermined position.

Whereas all drilling hook structures incorporate a relief spring, notall tubing hook structures are of this type. Many tubing hook structuresprovide for rotation of the hook member, with or without a releasablerotation lock, but with no axial movement of the hook member relative tothe supporting member. Accordingly, in the application of the instantinvention to this type of hook structure either the cam or its followermay be spring-mounted on one of the members of the hook structure, thusproviding for relative movement between the cam and its follower upondeflection of the spring. In this case the cooperating cam elements willconstantly urge the hook member into a predetermined oriented position,both while the hook is loaded and while it is unloaded, but will permitthe hook member to rotate if the rotational force is sufficient todeflect the cam spring.

The invention and its application to various types of hook structureswill be understood from the following detailed description of a drillinghook structure incorporating the invention, and of a typical tubing hookstructure having no relief spring but incorporating a different versionof the invention, reference being had to the accompanying drawingswherein:

Figure 1 is a view in side elevation of an unloaded spring-type drillinghook embodying the invention;

Figure 2 is a side elevational view taken at right angles to Figure 1;

Figure 3 is a view similar to Figure l but showing the hook loaded androtated through an angle of 180;

Figure 4 is a view similar to Figure 1 with parts broken away on acentral longitudinal plane;

Figure 5 is a transverse sectional view taken on line VV of Figure 4;

Figure 6 is a fragmentary longitudinal view taken on line VIVI of Figure5;

Figure 6a is a view similar to Figure 6 but showing the lockingmechanism in released position;

Figure 7 is a view in side elevation of a tubing hook of the non-springtype incorporating the instant invention;

Figure 8 is a view similar to Figure 7 but with parts broken away online VIII-VIII of Figure 9;

Figure 9 is a transverse sectional view taken on line IX-IX of Figure 8;

Figure 10 is a fragmentary sectional view taken on line X-X of Figure 7;

Figure 11 is a view in rear elevation of a modified form of theinvention applied to a book of the type shown in Figures 7 to 10; and

Figure 12 is a transverse sectional view taken on line XII-XII of Figure11.

Referring first to Figures 1 to 6, inclusive, wherein the invention isshown as embodied in a spring-type drilling hook structure, it will beobserved that the supporting member comprises generally a housing 2having a ball 4 attached to its upper extremity for suspending thestructure from a traveling block. The load carrying member includes amain shank 6 slidably and rotatably mounted in the housing 2, the lowerportion of the shank projecting below the housing and carrying a hookbody generally designated 8. An upwardly facing internal shoulder 10 isformed in the housing adjacent its lower end, on which rests a thrustbearing 12 which rotatably supports a lock ring 14 having a plurality oflocking recesses 16 in its peripheral surface. A locking member 18 ispivotally mounted in the housing 2 for movement selectively into or outof engagement with a selected recess 16.

In the foregoing and throughout the specification, as well as in theclaims, the conventional nomenclature commonly accepted throughout theindustry is utilized, thus the whole structure is designated as a hookstructure while the term hook or hook body refers only to theload-carrying member or members of the hook structure. Despite possibleconfusion between the term hook structure, hook, hook body" or hookelement, this terminology is adhered to as compatible with theliterature and prior patents of this art. Since common variations ofhook structures include many transpositions and rearrangements of parts,such for instance, as inclusion of the housing as a part of the hookmember and the shank as an element of the supporting member, thislanguage is deemed properly appropriate to describe the invention in thecommon parlance already established in this field.

A compression spring 20 is supported by the lock ring 14, the upper endof the spring having supporting engagement with a collar 22. A shankextension 24 is secured to the main shank 6 in coaxial relation thereto,the upper end of the shank extension being threaded to receive a nut 26by which the collar 22 is secured to the shank extension.

The major portion of the shank 6 is flattened on opposite sides toprovide a non-circular cross-section, as illustrated in Figure 5, andthe lock ring 14 is provided with a correspondingly shaped openingtherethrough, whereby the shank may slide freely through the lock ringbut is prevented from rotating with respect thereto. Above the flattenedportion of the shank 6 there is provided a cylindrical head 28 integralwith the flattened portion and forming a pair of downwardly facingshoulders 30 adapted to engage the lock ring 14 and thus limit theextent of compression of the spring.

The construction thus far described forms no part of the instantinvention, and is substantially as illustrated and described in UnitedStates Patent No. 2,506,593, granted May 9, 1950 to R. K. Hertel and G.F. Nicolson, to which reference may be had for a more detaileddisclosure of the construction.

As previously mentioned, the swivel locking member 18 is customarilydisengaged from the locking recesses 16 in the lock ring 14 when runningthe drill pipe into the well, in order not to restrain the drill pipefrom rotating if cork-screwing of the bit tends to rotate it. On theother hand, when the hook structure is unloaded during such operation,such as when it is being raised to pick up the next stand of pipe fromthe pipe rack, it is highly desirable that the hook body 8 assume apredetermined oriented position such that the lateral opening in theelevator faces the stand of pipe to be picked up. The instant invention,as applied to this type of hook structure, provides such predeterminedorientation of the hook body when it is unloaded'and also permits freerotation of the hook body while the hook body is supporting the weightof the drill string.

Referring to Figures 1 to 3, it will be noted that the lower portion ofthe housing 2 is provided with a downwardly facing annular cam surface32 which encircles the housing. This cam surface is formed on a sleeveor boss 34 which may either be an integral part of the housing or may bewelded or otherwise rigidly secured to the housing. As shown mostclearly in Figures 4 and 5, a collar 36 is secured by a transverse pin33 to the shank 6, the upper surface of the collar abutting the lowerend surface of the housing 2 when the hook body is unloaded and thuslimiting the upward movement of the shank under the expansive force ofthe spring 20. The collar 36 also serves to rotatably support a camfollower ring 40, and to this end the upper portion of the collar is ofreduced outer diameter, as indicated at 42 in Figure 6, providing asupporting shoulder 44 for the ring 40. A retaining ring 46 engages aninternal groove in the lower portion of the ring 40 and abuts againstthe underside of the collar 36 to retain the ring 40 on the shoulder 44.

The ring 40 is provided with an upward projection 48 in which is mounteda roller pin 50 on which is journaled a cam follower roller 52 which isadapted to coact with the cam surface 32 to effect predeterminedorientation of the hook body 8 with respect to the housing 2. It isconsidered desirable that the coaction of the cam and follower beeifective to orient the hook body into any one of a plurality ofangularly related positions. This may be accomplished by providing forangular adjustment of either the cam or the cam follower about the axisof the hook. in the illustrated embodiment the cam follower ring 4% isrotatably mounted on the collar 36 and releasable locking means areprovided whereby the ring may be locked in any adjusted position.

Referring particularly to Figures 5 and 6, it will be observed that theperiphery of the collar 36 is provided with a circumferential series ofteeth 54. A locking member 56 is movably mounted in a recess in the ring40 and has teeth 58 formed thereon which are adapted to intermesh with aselected group of the teeth 54. The locking member 56 may be retractedradially outwardly to disengage it from the collar 36, by means of anactuator 6t) journaled on a transverse pivot pin 62 mounted in the ring40. A convex locking surface 64 is formed on the actuator 60 and, asshown in Figure 6, engages a concave surface 66 on the locking member56. These surfaces are concentric with the axis of the pivot pin 62whereby any radially outward component of thrust exerted on the lockingmember 56 by the beveled teeth 54 and 58 will be transmitted radiallytoward the axis of the pivot pin 62, with no tendency to rotate theactuator 60 in either direction.

The locking member 56 is provided with a pair of outwardly extendingarms 70 interconnected at their outer extremities by a cross arm 72. Theactuator 66 is provided with a pair of pivot bosses 73 with alignedbores to receive a pivot pin 74, on which is journaled the head portionof a plunger 76. The plunger head is rounded and projects into a recess78 formed in the actuator 6%. The opposite end of the plunger projectsthrough an opening 79 in the upper wall of the ring 46, and acompression spring 80 is interposed between the plunger head and theinner surface of the ring 40. It will be noted that in Figure 6 theplunger pivot pin 74 is disposed to the right of a line extendingbetween the axis of the actuator pivot pin 62 and the free end of theplunger, whereby the plunger spring 80 biases the actuator into lockingposition. Upon depressing the lever portion 82 of the actuator 60, theplunger pivot pin 74 is moved outwardly in an arcuate path about theaxis of the actuator pivot pin 62, thus causing the plunger 76 to rockabout its free end which is loosely pivoted in the wall opening 79. Itwill be understood that the locking member 56 cannot move outwardlyuntil the locking surface 64 on the actuator is fullyv disengaged fromthe cooperating locking surface 66 on the member 56. When this conditionis attained, a slight additional movement of the actuator 66 causes thehead of the plunger 76 to engage the cross arm 72, whereupon continuedmovement of the actuator moves the locking member 56 outwardly todisengage the teeth 58 from the teeth 54. The final position of theactuator is shown in Figure 6a, wherein it will be noted that theplunger pivot pin 74 is disposed outwardly of a line extending betweenthe axis of the actuator pivot pin 62 and the free end of the plunger.The spring 80 thus biases the actuator 60 and the locking member 56toward their released positions. The ring 40 may then be rotated intoanother position and locked therein by raising the actuator lever 82upwardly and returning the locking mechanism to the position shown inFigure 6.

The operation of the above-described positioning device is as follows:When the elevator is disengaged from the drill string the hook spring 20is expanded and the hook elements assume the relative positions shown inFigures 1, 2 and 4, with the cam follower roller 52 at the uppermostpoint on the cam surface 32. Whenrunning the drill pipe into the wellthe hook structure and the empty elevator are raised in the derrick toengage the elevator with the upper end'of a stand of pipe in the piperack, whereupon the stand is lifted off the rack and connected to theupper end of the drill string supported in the rotary table. The weightof the entire drill string is then taken on the hook body, which causesthe hook spring to be compressed and the hook body 8 and its shank 6 tomove downwardly, as indicated in Figure 3. In this position the camfollower roller is disposed below the lowermost point on the cam surface32, and hence the hook body and shank are free to rotate about the axisof the shank. It will be understood that during this sequence ofoperations the conventional swivel lock 18 is disengaged from thelooking recesses 16 in the lock ring 14. Accordingly, any tendency ofthe drill string to rotate as it is being lowered, as a result ofcorkscrewing of the bit, is entirely unrestricted and consequently theotherwise existing hazard of unscrewing a joint in the drill string iseliminated.

When the drill string has been lowered the length of the added stand,the pipe slips are set and the Weight of the drill string is transferredto the slips by slightly lowering the hook structure. This allows thespring 20 to expand and raise the hook body. In the absence of thepositioning device, if the hook body should have drifted from itsinitially oriented position as a result of rotation of the pipe duringlowering, it would be necessary for the floor crew to grasp the elevatoror links and re-orient the hook body so that the elevator opening facesthe next stand of pipe to be picked up from the pipe rack. However, ifthe hook structure is equipped with a positioning device according tothis invention, upon upward movement of the hook body the cam followerroller 52 engages the cam surface 32, whereupon the upward spring forceproduces a torsional component causing the roller to move along the upwardly inclined cam surface and into its initial position. The hook bodyand elevator are thus automatically re-oriented into proper position forengaging another stand of pipe.

Adjustment of the predetermined oriented position of the hook body andelevator to accommodate varying rig conditions may be quickly and easilyeffected while the hook structure is unloaded, by rocking the actuator82 downwardly to disengage the locking member 56 from the teeth 54 onthe collar 36. The hook body 8, shank 6 and collar 36 may then berotated the desired amount while the follower ring 40 is held againstrotation by the engagement of the roller 52 with the cam surface 32. Thelocking member 56 is then re-engaged with the collar 36 to lock thefollower ring 40 in its new position.

It will be observed by reference to Figure 2 that the uppermost portionof the cam surface 32 is provided with a shallow arcuate depression orrecess 84, and that the roller 52 has slight clearance with the Wall ofthis recess. This clearance exists because of the fact that furtherupward movement of the hook body and shank is prevented by engagement ofthe upper surface of the shank collar 36 with the lower end of thehousing By reason of this clearance the roller 52 and its supportingelements are relieved of the upward spring thrust when in this position.Also, by reason of this clearance a slight freedom of oscillation of thehook body is permitted before the roller engages the cam surface. Thisis considered desirable in order to permit the elevator to oscillateslightly to accommodate itself to the pipe stands while being appliedthereto.

Although in the embodiment of the invention above described the camsurface 32 is associated with the housing 2 or other main supportingmember and the cam follower is associated with the hook body or otherloadcarrying member, it will be appreciated that this arrangement may bereversed by mounting the cam follower on the housing and providing thecam surface on the spring-supported load-carrying sub-assembly. It willalso be apparent that in lieu of providing for angular adjustment of thecam follower about the axis of the shank into various selectedpositions, the cam sleeve 34 on which the cam surface 36 is formed mayalternatively be angularly adjustable relative to the hook element onwhich it is mounted. An example of this alternative construction isshown in the embodiment illustrated in Figures 7 to 10, inclusive.

In the embodiment of the invention shown in Figures 1 to 6, inclusive,and described above, the torsional force required to rotate theload-carrying hook element and the elevator into its predeterminedoriented position is derived from the hook relief spring, and suchrotation occurs during relative axial movement between the load-carryingand supporting elements of the hook structure. The invention is alsosusceptible of being incorporated in hook structures which do notincorporate relief springs and in which there is no relative axialmovement between the conventional elements thereof. An example of thisis shown in Figures 7 to 10, inelusive.

Referring to those figures, the hook structure illustrated therein istypical of the type employed when running well production tubing intoand out of wells. In such operations the string of tubing is broken downinto stands and racked in the derrick or in the mast of the pulling unitin much the same manner as with drill pipe. Hence the same advantagesaccrue from the use of a positioning device on such a hook structure. Asshown, the hook structure comprises generally a supporting member 102having a bail portion 104 for attaching it to a traveling block, andhaving an upwardly facing annular shoulder 106 forming a seat for abearing 108. The load-carrying member comprises a hook body 110 providedwith an integral shank 112 the upper portion of which is threaded toreceive a nut 114 which is supported on the bearing 108, thus rotatablysupporting the hook body 110 by the supporting member 102.

In this embodiment of the invention a cam sleeve 116 is associated withthe supporting member 102 and has a downwardly facing cam surface 118formed thereon. A cam follower roller 126 is associated with the hookbody 110, being journaled on a pin 122 carried by a roller support 124.In this instance the cam ac tion is provided by a vertical spring 126interposed between the roller support 124 and the hook body andconstantly urging the roller upwardly into engagement with the camsurface 118. The major portion of the roller support is of hollowcylindrical form and is telescoped within an upwardly facing recessformed in the hook body, as by drilling the body or, as shown, bywelding or otherwise securing a sleeve 128 to the side of the hook body.

It will be apparent that with this arrangement any rotation of the hookbody from the position shown will esult in compression of the spring 126as the roller 12% moves downwardly along the inclined cam surface 118.The upward force exerted by the spring 126 develops, by the eoaction ofthe roller and the cam surface 118, a torsional component of forcetending to rotate the hook body back to its initially oriented position.Hence upon release or subsidence of the opposing torsional force thehook body automatically returns to its initial position. It will benoted that unlike the previous embodiment, the hook body is urged alwaysto its initially oriented position whether loaded or unloaded. In thisembodiment of the invention it is more convenient to provide forvariation of the predetermined orientation of the hook body by mountingthe cam sleeve 116 for angular adjustment about the axis of the shank112, and to provide releasable locking mechanism between the sleeve andthe supporting member 102. The sleeve may be journaled on the supportingmember and supported against upward or downward movement relativethereto by a combined radial and thrust bearing consisting of bearingelements 130 confined between complementary bearing races 132 and 134 inthe sleeve and supporting member. The bearing elements may be insertedinto the bearing race through a filler opening 13-6 (Figures 7 and 10)closed by a plug 138.

The cam ring 116 may be releasably locked against rotation by lockingmechanism such as a locking member 146 pivotally mounted by a pivot pin142 in a recess in the cam ring. The locking member may be provided withteeth 144 (Figure 9) adapted to be moved into or out of engagement withany one of a selected group of teeth 146 formed on the supporting member102. A plunger 148 and a compression spring 150 are mounted in a bore inthe locking member, the protruding end of the plunger being beveled onopposite sides and being adapted to ride over a boss 152 on the cam ringas the locking member is rocked about its axis. In this manner thelocking member is yieldably retained in either locking or releasedposition. The pivot pin 142 is keyed to the locking member and extendsthrough the wall of the recess to the exterior of the cam ring, anactuator lever 154 being secured to the protruding end of the pivot pinto enable an operator to manipulate the locking member.

When it is desired to change the oriented position of the hook body therotation lock is released by raising the actuator lever 154, and uponturning the hook body the engagement of the roller 120 with the camsurface 118 causes the cam ring 116 to turn with the hook body. Uponassuming the desired position the rotation lock is manipulated tolocking position by depressing the lever 154.

In the embodiment shown in Figures 11 and 12 a different type of cam andfollower is incorporated in a hook structure of the type illustrated inFigures 7 to 10, inclusive. In this embodiment the cam is of the radialcam type, providing a peripheral cam surface 162 which is eccentric withrespect to the axis of the hook shank 164. For simplicity, the cam isshown as an integral part of the supporting member 166, although it willbe understood that if preferred it may be formed as a separate memberadjustably mounted on the supporting member, or on the hook body 168 inwhich case the cam follower would be mounted on the supporting member.

In this instance the cam follower comprises a roller 170 journaled onthe free end of an arm 172 which is pivotally supported at its other endon a vertical pivot pin 174 secured to the hook body 168. A torsionspring 176 encircles the pivot pin 174, the upper end of the springabutting a lug 178 formed on the arm 172 and the other end of the springabutting a lug 180 formed on the hook body. The arm 172 is thus biasedinwardlyv by the spring to press the roller into engagement with the camsurface 162.

Upon rotation of the hook body out of the position shown, force exertedby the spring 176 and acting through the roller 17b and the cam surface162 develops a torsional moment of force about the axis of the hookshank, tending to rotate the hook body back to its original position.

It will be observed that as in the embodiment shown in Figures 1 to 6,inclusive, a shallow arcuate recess 84 is formed at the neutral point ofcam surfaces 118 and 162 respectively of the embodiments shown inFigures 7 to 10 and Figures 11 and 12. In the latter two cases, however,the rollers 120 and 170 engage the walls of the respective recesses andthus yieldably retain the hook body in a predetermined oriented positionwith substantially no play. It will be apparent, however, that if someslight freedom of. movement of the hook body to either side of theneutral point is desired, this may be rendered possible by lengtheningthe recesses 84 and providing therein a non-camming surface of thedesired length, over which the roller may travel without deflecting thespring. Such freedom of movement could also be obtained by providing astop means for the roller support 124 or arm 172.

From the foregoing description of several forms which this invention mayassume, and illustrating its application to two different types of hookstructures, it will be apparent that it is applicable to various typesof hook structures which may vary widely in construction so long as theyprovide for rotation of the load-carrying member relative to thesupporting member. Various forms of cams may be employed, and thearrangement whereby the predetermined orientation of the load-carryingmember may be changed may assume various forms. While in each of theembodiments illustrated the cam is of the constant-angle type, it willbe understood that variableangle cams may be employed and thus vary theratio of the spring force to the torsional component of force acting onthe load-carrying member.

It is to be understood, therefore, and it will be apparent to thoseskilled in the art, that other modifications and changes may be madewithout departing from the essence of the invention, and it is intendedto cover herein all such modifications and changes as are embracedwithin the true scope and spirit of the appended claims.

I claim:

1. A book structure for use in raising or lowering well pipe or rodscomprising, in combination: a supporting member having means forconnecting said hook structure to raising and lowering means; aload-carrying member rotatively supported by said supporting member andhaving means for suspending a load therefrom; cooperating cam elementscarried respectively by said members; and means urging one of said camelements toward the other cam element to cause said elements to biassaid load-carrying member into a predetermined oriented positionrelative to said supporting member.

2. A hook structure comprising in combination: a supporting member; aload-carrying member rotatively supported by said supporting member;cooperating cam elements carried respectively by said members; meansurging one of said cam elements toward the other cam elements wherebysaid elements may coact to bias said load-carrying member about its axisof rotation into a predetermined oriented position relative to saidsupporting member; one of said elements being adjustable relative to itsrespective member about the rotative axis of said load-carrying member;and means for releasably securing said adjustable element in diflerentadjusted positions whereby to provide a plurality of selective prede- 10terrnined oriented positions of said load-carrying member.

3. A book structure comprising the combination of: a supporting member;a load-carrying member rotatively supported by said supporting member;cooperating cam elements carried respectively by said members; springmeans urging one of said cam elements toward the other cam elementwhereby said cam elements may coact to cause said spring means to exerta force tending to rotate said load-carrying member into a predeterminedoriented position relative to said supporting member; one of saidelements being adjustable relative to its respective member about therotative axis of said loadcarrying member;'and means for releasablysecuring said adjustable element in different adjusted positions wherebyto provide a plurality of selective predetermined oriented positions ofsaid load-carrying member.

4. A hook structure for use in raising or lowering well pipe or rodscomprising, in combination: a supporting member having means forconnecting said hook structure to raising and lowering means; aload-carrying member rotatively supported by said supporting member andhaving means for suspending a load therefrom; a cam element carried bysaid supporting member and having a cam surface thereon; a cam followerelement carried by said load-carrying member and engageable with saidcam surface; and means urging one of said elements toward the otherelement in a direction to exert a force tending to maintain saidload-carrying member in a predetermined oriented position relative tosaid supporting member.

5. A hook structure comprising the combination of: a supporting member;a load-carrying member rotatively supported by said supporting member; acam element carried by said supporting member and having a cam surfacethereon; a cam follower element carried by said loadcarrying member andengageable with said cam surface; means urging one of said elementstoward the other in a direction to exert a force tending to maintainsaid loadcarrying member in a predetermined oriented position relativeto said supporting member; one of said elements being adjustablerelative to its respective member about the rotative axis of saidload-carrying member; and means for releasably securing said adjustableelement in different adjusted positions whereby to provide a pluralityof selective predetermined oriented positions of said loadcarryingmember.

6. In a hook structure, the combination of: a supporting member; aload-carrying member carried by said supporting member for rotationrelative thereto and for limited longitudinal movement relative theretobetween first and second longitudinally spaced positions; resilientmeans interposed between said members yieldingly urging saidload-carrying member toward said first position and being yieldable topermit longitudinal movement of said load-carrying member toward saidsecond position; and cooperating elements on said members operable toprevent relative rotation between said members when said load-carryingmember is in said first position, said elements being renderedinelfective to prevent said rotation upon movement of said load-carryingmember into said second position.

7. A hook structure as set forth in claim 6, wherein said cooperatingelements coact to insure return of said load-carrying member to apredetermined oriented position with respect to said supporting memberduring movement of said load-carrying member from said second positionto said first position.

8. A hook structure as set forth in claim 7, wherein one of saidelements is angularly adjustable relative to its associated member aboutthe axis of rotation of said load-carrying member to vary saidpredetermined oriented position.

9. In a hook structure, the combination of: a supporting member; aload-carrying member carried by said supporting member for rotationrelative thereto and for limited longitudinal movement relative theretobetween first and second longitudinally spaced positions; resilientmeans interposed between said members yieldingly urging saidload-carrying member toward said first position and being yieldable topermit longitudinal movement of said load-carrying member toward saidsecond position; and cooperating cam elements comprising a cam and a camfollower, one associated with each of said members, said cam elementscoacting during movement of said load-carrying member toward said firstposition, in the event of relative rotation between said members whensaid load-carrying member is in said second position, to develop fromthe stored energy in said resilient means a torsional component of forceacting between said members to rotate said load-carrying member into apredetermined oriented position with respect to said supporting memberwhen said load-carrying member assumes said first position.

10. A hook structure for use in raising or lowering well pipe or rodscomprising, in combination: a supporting member having means forconnecting said hook structure to raising and lowering means; aload-carrying member rotatively supported by said supporting member andhaving means for suspending a load therefrom; one of said membersincluding a housing and the other member including a shouldered shankaxially slidable and rotatable in said housing; a compression springinterposed between the shank shoulder and the housing for resistingaxial movement of said shank relative to said housing in one direction,said spring being compressible to permit such movement; and cooperatingcam elements comprising a cam and a cam follower, one associated withsaid housing and the other associated with said shank, said cam elementscoacting during expansion of said spring, in the event of relativerotation between said shank and housing, to cam said housing and shankinto predetermined oriented relation when said spring is fully expanded.

11. A hook structure as set forth in claim 10, wherein said cam elementsare ineffective to prevent relative rotation between said housing andsaid shank when said spring is fully compressed.

12. A hook structure comprising the combination of: a supporting member;a load-carrying member rotatively supported thereby; a pair ofcooperating cam elements comprising a cam and a cam follower, onecarried respectively by each of said members; spring means actingbetween one of said cam elements and its respective membet and urgingsaid one cam element toward the other cam element; said cam elementscoacting to cause said spring means to exert a torsional component offorce biasing said load-carrying member about its rotative axis into apredetermined oriented position relative to said supporting member inthe event of prior departure of said member from said predeterminedoriented position.

13. A hook structure comprising the combination of: a. supportingmember; a load-carrying member rotatively supported thereby; cooperatingcam elements carried respectively by said members; spring means actingbetween one of said cam elements and its respective member and urgingsaid one cam element toward the other cam element; said cam elementscoacting to cause said spring means to exert a torsional force biasingsaid load-carrying member about its rotative axis into a predeterminedoriented position relative to said supporting member in the event ofprior departure of said member from said predetermined orientedposition; one of said elements being adjustable relative to itsrespective member about the rotative axis of said load-carrying member;and means for releasably securing said adjustable element in diflerentadjusted positions whereby to provide a plurality of selectivepredetermined oriented positions of said load-carrying member.

14. A hook structure as set forth in claim 12, wherein said cam includesa cam surface concentric with respect to the rotative axis of saidload-carrying member and inclined with respect to a plane normal to saidaxis, and wherein said cam follower is movable in a directionsubstantially parallel to said axis.

15. A hook structure as set forth in claim 12, wherein said cam includesa cam surface eccentric with respect to the axis of rotation of saidload-carrying member, and wherein said cam follower is movable in adirection substantially normal to said axis.

References Cited in the file of this patent UNITED STATES PATENTS

